This is a continuation of the previous changes titled:
Btrfs: fix incremental send's decision to delay a dir move/rename
Btrfs: part 2, fix incremental send's decision to delay a dir move/rename
There's a few more cases where a directory rename/move must be delayed which was
previously overlooked. If our immediate ancestor has a lower inode number than
ours and it doesn't have a delayed rename/move operation associated to it, it
doesn't mean there isn't any non-direct ancestor of our current inode that needs
to be renamed/moved before our current inode (i.e. with a higher inode number
than ours).
So we can't stop the search if our immediate ancestor has a lower inode number
than
ours, we need to navigate the directory hierarchy upwards until we hit the root
or:
1) find an ancestor with an higher inode number that was renamed/moved in the
send
root too (or already has a pending rename/move registered);
2) find an ancestor that is a new directory (higher inode number than ours and
exists only in the send root).
Reproducer for case 1)
$ mkfs.btrfs -f /dev/sdd
$ mount /dev/sdd /mnt
$ mkdir -p /mnt/a/b
$ mkdir -p /mnt/a/c/d
$ mkdir /mnt/a/b/e
$ mkdir /mnt/a/c/d/f
$ mv /mnt/a/b /mnt/a/c/d/2b
$ mkdir /mnt/a/x
$ mkdir /mnt/a/y
$ btrfs subvolume snapshot -r /mnt /mnt/snap1
$ btrfs send /mnt/snap1 -f /tmp/base.send
$ mv /mnt/a/x /mnt/a/y
$ mv /mnt/a/c/d/2b/e /mnt/a/c/d/2b/2e
$ mv /mnt/a/c/d /mnt/a/h/2d
$ mv /mnt/a/c /mnt/a/h/2d/2b/2c
$ btrfs subvolume snapshot -r /mnt /mnt/snap2
$ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send
Simple reproducer for case 2)
$ mkfs.btrfs -f /dev/sdd
$ mount /dev/sdd /mnt
$ mkdir -p /mnt/a/b
$ mkdir /mnt/a/c
$ mv /mnt/a/b /mnt/a/c/b2
$ mkdir /mnt/a/e
$ btrfs subvolume snapshot -r /mnt /mnt/snap1
$ btrfs send /mnt/snap1 -f /tmp/base.send
$ mv /mnt/a/c/b2 /mnt/a/e/b3
$ mkdir /mnt/a/e/b3/f
$ mkdir /mnt/a/h
$ mv /mnt/a/c /mnt/a/e/b3/f/c2
$ mv /mnt/a/e /mnt/a/h/e2
$ btrfs subvolume snapshot -r /mnt /mnt/snap2
$ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send
Another simple reproducer for case 2)
$ mkfs.btrfs -f /dev/sdd
$ mount /dev/sdd /mnt
$ mkdir -p /mnt/a/b
$ mkdir /mnt/a/c
$ mkdir /mnt/a/b/d
$ mkdir /mnt/a/c/e
$ btrfs subvolume snapshot -r /mnt /mnt/snap1
$ btrfs send /mnt/snap1 -f /tmp/base.send
$ mkdir /mnt/a/b/d/f
$ mkdir /mnt/a/b/g
$ mv /mnt/a/c/e /mnt/a/b/g/e2
$ mv /mnt/a/c /mnt/a/b/d/f/c2
$ mv /mnt/a/b/d/f /mnt/a/b/g/e2/f2
$ btrfs subvolume snapshot -r /mnt /mnt/snap2
$ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send
More complex reproducer for case 2)
$ mkfs.btrfs -f /dev/sdd
$ mount /dev/sdd /mnt
$ mkdir -p /mnt/a/b
$ mkdir -p /mnt/a/c/d
$ mkdir /mnt/a/b/e
$ mkdir /mnt/a/c/d/f
$ mv /mnt/a/b /mnt/a/c/d/2b
$ mkdir /mnt/a/x
$ mkdir /mnt/a/y
$ btrfs subvolume snapshot -r /mnt /mnt/snap1
$ btrfs send /mnt/snap1 -f /tmp/base.send
$ mv /mnt/a/x /mnt/a/y
$ mv /mnt/a/c/d/2b/e /mnt/a/c/d/2b/2e
$ mv /mnt/a/c/d /mnt/a/h/2d
$ mv /mnt/a/c /mnt/a/h/2d/2b/2c
$ btrfs subvolume snapshot -r /mnt /mnt/snap2
$ btrfs send -p /mnt/snap1 /mnt/snap2 -f /tmp/incremental.send
For both cases the incremental send would enter an infinite loop when building
path strings.
While solving these cases, this change also re-implements the code to detect
when directory moves/renames should be delayed. Instead of dealing with several
specific cases separately, it's now more generic handling all cases with a
simple
detection algorithm and if when applying a delayed move/rename there's a path
loop
detected, it further delays the move/rename registering a new ancestor inode as
the dependency inode (so our rename happens after that ancestor is renamed).
Tests for these cases is being added to xfstests too.
Signed-off-by: Filipe David Borba Manana <fdman...@gmail.com>
---
fs/btrfs/send.c | 190 ++++++++++++++++++++++++++++---------------------------
1 file changed, 96 insertions(+), 94 deletions(-)
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 2952889..e2e422c 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -2914,7 +2914,9 @@ static void free_waiting_dir_move(struct send_ctx *sctx,
static int add_pending_dir_move(struct send_ctx *sctx,
u64 ino,
u64 ino_gen,
- u64 parent_ino)
+ u64 parent_ino,
+ struct list_head *new_refs,
+ struct list_head *deleted_refs)
{
struct rb_node **p = &sctx->pending_dir_moves.rb_node;
struct rb_node *parent = NULL;
@@ -2946,12 +2948,12 @@ static int add_pending_dir_move(struct send_ctx *sctx,
}
}
- list_for_each_entry(cur, &sctx->deleted_refs, list) {
+ list_for_each_entry(cur, deleted_refs, list) {
ret = dup_ref(cur, &pm->update_refs);
if (ret < 0)
goto out;
}
- list_for_each_entry(cur, &sctx->new_refs, list) {
+ list_for_each_entry(cur, new_refs, list) {
ret = dup_ref(cur, &pm->update_refs);
if (ret < 0)
goto out;
@@ -2994,6 +2996,48 @@ static struct pending_dir_move
*get_pending_dir_moves(struct send_ctx *sctx,
return NULL;
}
+static int path_loop(struct send_ctx *sctx, struct fs_path *name,
+ u64 ino, u64 gen, u64 *ancestor_ino)
+{
+ int ret = 0;
+ u64 parent_inode = 0;
+ u64 parent_gen = 0;
+ u64 start_ino = ino;
+
+ *ancestor_ino = 0;
+ while (ino != BTRFS_FIRST_FREE_OBJECTID) {
+ fs_path_reset(name);
+
+ if (is_waiting_for_rm(sctx, ino))
+ break;
+ if (is_waiting_for_move(sctx, ino)) {
+ if (*ancestor_ino == 0)
+ *ancestor_ino = ino;
+ ret = get_first_ref(sctx->parent_root, ino,
+ &parent_inode, &parent_gen, name);
+ } else {
+ ret = __get_cur_name_and_parent(sctx, ino, gen,
+ &parent_inode,
+ &parent_gen, name);
+ if (ret > 0) {
+ ret = 0;
+ break;
+ }
+ }
+ if (ret < 0)
+ break;
+ if (parent_inode == start_ino) {
+ ret = 1;
+ if (*ancestor_ino == 0)
+ *ancestor_ino = ino;
+ break;
+ }
+ ino = parent_inode;
+ gen = parent_gen;
+ }
+ return ret;
+}
+
static int apply_dir_move(struct send_ctx *sctx, struct pending_dir_move *pm)
{
struct fs_path *from_path = NULL;
@@ -3005,6 +3049,7 @@ static int apply_dir_move(struct send_ctx *sctx, struct
pending_dir_move *pm)
struct waiting_dir_move *dm = NULL;
u64 rmdir_ino = 0;
int ret;
+ u64 ancestor = 0;
name = fs_path_alloc();
from_path = fs_path_alloc();
@@ -3031,11 +3076,25 @@ static int apply_dir_move(struct send_ctx *sctx, struct
pending_dir_move *pm)
if (ret < 0)
goto out;
+ sctx->send_progress = sctx->cur_ino + 1;
+ ret = path_loop(sctx, name, pm->ino, pm->gen, &ancestor);
+ if (ret) {
+ LIST_HEAD(deleted_refs);
+ ASSERT(ancestor > BTRFS_FIRST_FREE_OBJECTID);
+ ret = add_pending_dir_move(sctx, pm->ino, pm->gen, ancestor,
+ &pm->update_refs, &deleted_refs);
+ if (ret < 0)
+ goto out;
+ if (rmdir_ino) {
+ dm = get_waiting_dir_move(sctx, pm->ino);
+ ASSERT(dm);
+ dm->rmdir_ino = rmdir_ino;
+ }
+ goto out;
+ }
fs_path_reset(name);
to_path = name;
name = NULL;
-
- sctx->send_progress = sctx->cur_ino + 1;
ret = get_cur_path(sctx, pm->ino, pm->gen, to_path);
if (ret < 0)
goto out;
@@ -3159,127 +3218,74 @@ out:
static int wait_for_parent_move(struct send_ctx *sctx,
struct recorded_ref *parent_ref)
{
- int ret;
+ int ret = 0;
u64 ino = parent_ref->dir;
u64 parent_ino_before, parent_ino_after;
- u64 old_gen;
struct fs_path *path_before = NULL;
struct fs_path *path_after = NULL;
int len1, len2;
- int register_upper_dirs;
- u64 gen;
-
- if (is_waiting_for_move(sctx, ino))
- return 1;
-
- if (parent_ref->dir <= sctx->cur_ino)
- return 0;
-
- ret = get_inode_info(sctx->parent_root, ino, NULL, &old_gen,
- NULL, NULL, NULL, NULL);
- if (ret == -ENOENT)
- return 0;
- else if (ret < 0)
- return ret;
-
- if (parent_ref->dir_gen != old_gen)
- return 0;
-
- path_before = fs_path_alloc();
- if (!path_before)
- return -ENOMEM;
-
- ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before,
- NULL, path_before);
- if (ret == -ENOENT) {
- ret = 0;
- goto out;
- } else if (ret < 0) {
- goto out;
- }
path_after = fs_path_alloc();
- if (!path_after) {
+ path_before = fs_path_alloc();
+ if (!path_after || !path_before) {
ret = -ENOMEM;
goto out;
}
- ret = get_first_ref(sctx->send_root, ino, &parent_ino_after,
- &gen, path_after);
- if (ret == -ENOENT) {
- ret = 0;
- goto out;
- } else if (ret < 0) {
- goto out;
- }
-
- len1 = fs_path_len(path_before);
- len2 = fs_path_len(path_after);
- if (parent_ino_before != parent_ino_after || len1 != len2 ||
- memcmp(path_before->start, path_after->start, len1)) {
- ret = 1;
- goto out;
- }
- ret = 0;
-
/*
- * Ok, our new most direct ancestor has a higher inode number but
- * wasn't moved/renamed. So maybe some of the new ancestors higher in
- * the hierarchy have an higher inode number too *and* were renamed
- * or moved - in this case we need to wait for the ancestor's rename
- * or move operation before we can do the move/rename for the current
- * inode.
+ * Our current directory inode may not yet be renamed/moved because some
+ * ancestor (immediate or not) has to be renamed/moved first. So find if
+ * such ancestor exists and make sure our own rename/move happens after
+ * that ancestor is processed.
*/
- register_upper_dirs = 0;
- ino = parent_ino_after;
-again:
- while ((ret == 0 || register_upper_dirs) && ino > sctx->cur_ino) {
- u64 parent_gen;
+ while (ino > BTRFS_FIRST_FREE_OBJECTID) {
+ if (is_waiting_for_move(sctx, ino)) {
+ ret = 1;
+ break;
+ }
fs_path_reset(path_before);
fs_path_reset(path_after);
ret = get_first_ref(sctx->send_root, ino, &parent_ino_after,
- &parent_gen, path_after);
+ NULL, path_after);
if (ret < 0)
goto out;
ret = get_first_ref(sctx->parent_root, ino, &parent_ino_before,
NULL, path_before);
- if (ret == -ENOENT) {
- ret = 0;
- break;
- } else if (ret < 0) {
+ if (ret < 0 && ret != -ENOENT) {
goto out;
+ } else if (ret == -ENOENT) {
+ ret = 1;
+ break;
}
len1 = fs_path_len(path_before);
len2 = fs_path_len(path_after);
- if (parent_ino_before != parent_ino_after || len1 != len2 ||
- memcmp(path_before->start, path_after->start, len1)) {
+ if (ino > sctx->cur_ino &&
+ (parent_ino_before != parent_ino_after || len1 != len2 ||
+ memcmp(path_before->start, path_after->start, len1))) {
ret = 1;
- if (register_upper_dirs) {
- break;
- } else {
- register_upper_dirs = 1;
- ino = parent_ref->dir;
- gen = parent_ref->dir_gen;
- goto again;
- }
- } else if (register_upper_dirs) {
- ret = add_pending_dir_move(sctx, ino, gen,
- parent_ino_after);
- if (ret < 0 && ret != -EEXIST)
- goto out;
+ break;
}
-
ino = parent_ino_after;
- gen = parent_gen;
}
out:
fs_path_free(path_before);
fs_path_free(path_after);
+ if (ret == 1) {
+ ret = add_pending_dir_move(sctx,
+ sctx->cur_ino,
+ sctx->cur_inode_gen,
+ ino,
+ &sctx->new_refs,
+ &sctx->deleted_refs);
+ if (!ret)
+ ret = 1;
+ }
+
return ret;
}
@@ -3440,10 +3446,6 @@ verbose_printk("btrfs: process_recorded_refs %llu\n",
sctx->cur_ino);
if (ret < 0)
goto out;
if (ret) {
- ret = add_pending_dir_move(sctx,
- sctx->cur_ino,
- sctx->cur_inode_gen,
- cur->dir);
*pending_move = 1;
} else {
ret = send_rename(sctx, valid_path,
--
1.7.10.4
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